Introduction: Physiology of reproduction is very complex and many factors influence on animal infertility.Today, researchers simulate weightlessness physiology for investigation about space biology. The best successful model for microgravity physiology simulation on the floor is in the rat hind-limb suspenion .The aim of this study is evaluation and comparision of the effect of vitamin E on the reproductive male Rat system in weightlessness simulation on the ground (with and without vitamin E).

Materials and Methods: We dividid 28 adult male rats (Wistar) with three mounths old age and an 250 gram average weight ,into four groups with 7 number in each group, and researched on them. All rats were in the same condition for a week to adapt. Then we entered and analyzed collected data in SPSS version 23 software . We used wilcoxon test for before-after comparision and manwhitney-u test for two independent group comparision. We considered P- valu less than 0/05, statistically significant .

Result : The FSH levels in rats induced by microgravity plus vitamin E injection, was 41/0 ± 6/2 in the first, 57/0 ± 74/3 in the fourtheen day. The LH levels was 38/0 ± 43/0 in the first and 33/0 ± 62/0 in the last and testoseron level was 51/0 ± 55/1 in the first and 28/0 ± 5/1 in the last . In the rats without suspension and with vitamin E injection,the amount of LH was 43/0 ± 64/0 at first and 007/0 ± 17/0 in the last, the FSH level was 57/0 ± 16/3 in the first day and 49/0 ± 05/3 in the final and the testosteron level was 25/0 ± 52/1 in the first and 86/2 ± 22/3 in the fourtheen day.

Conclusion: In the rats under microgravity , testosteron decreases and LH, FSH increases. Vitamin E injection increases male Rats fertility in microgravity simulation too in comparision to the same group without this injection.